Nanotechnology is the creation of USEFUL/FUNCTIONALmaterials, devices and systems through manipulation of matterat nanometer scale and exploitation of novel phenomenawhich arise because of the nanometer sizes.

-9

Physical Dimension

CPU Clock SpeedAverage Transistor “Price”

Component Density

$1 / transistor

100 Nano$ / transistor

x 107

Transistor can not be scaled forever Silicon is no longer the best computing material No device solution to deal with power dissipation crisis

Manufacturing cost will soar

Scientific and industry research communities are looking for: Technology that sustains the spirit of Moore’s Law Materials that are much better than silicon Devices that are more energy-efficient (e.g., non-charge-based) Fabrication processes that are much cheaper, self-controlled,

dependable, and sustainable

The smallest silicon field-effect transistor (2001) Extremely aggressive litho patterning and fabrication Atomically thin gate dielectric layer (~8Å EOT) At supply voltage of 0.8V: CV/I delays are 0.29 ps

(3.45THz) for n-FET and 0.68 ps (1.47THz) for p-FET

~ 8A equivalent oxide thickness

Fin-memory (2006)FinFET (2006)FinFET (2003) FinFET SRAM (2005)

Low Dimensionality? Best electrostatics Smallest structure for carrier transport (1-D) Energy–efficiency design Quantum confinement/carrier mobility Device-interconnect “co-design”

“Top-Down” technology limits, costs

Reduction of FET “Dimensionality”

Multi-gate FET

Bio-mimeticmolecularcomputing

SNW/CNT devices

Bio-systemselectronics interface

Ultra highdensitystorage Computing Capacity

RLV

e-

Nano-electroniccomponents

Europa Sub

Robot ColonySensor Web

Nanotechnology is the “enabling technology” driving numerous applications. The core concept of “bottom-up” is to employ cheap chemistry to promote self-

assembly of functional components. New materials and technologies are emerging for energy-efficient information

processing devices.

Hierarchical AssemblyNano-systems

Inorganic CrystallineNanostructures

Organic/Bio MolecularNanostructures

tubewire

beltdisk

cubesaw

tetrapod combmonolayer wire

Singlemolecule

supramolecules

windmill

Self-assemblyNano-components

Crystal growth

Reaction chemistry Surface chemistryOrganic synthesis

Molecular engineeringMaterial synthesis

Solution-Phase Synthesis Solution-Liquid-Solid (SLS) Method Solvothermal Chemical Synthesis Template-Based Synthesis

Gas-Phase Synthesis Vapor-Liquid-Solid (VLS) Method

Laser ablation PVD CVD (thermal CVD, LPCVD,

PECVD, MOCVD) Vapor-Solid (VS) Method Oxide-Assisted Growth (OAG)

Thermal CVD

Thermal PVD

10+ types of low-dimensional nanostructures within five major categories:IV group elemental semiconductors (Si, Ge): computing/data storageIII-V group compound semiconductor (InSb): computing, spintronics, optoelectronics, TEMetal oxide (ZnO, TiO2): solar cell, spintronics, sensorsChalcogenides (GeTe, GeSb, Ge2Sb2Te5, Sb2Te3): phase-change memoryFerroelectric metal oxide (BaTiO3): data storage

Material characterizationPhysical morphology (SEM, TEM), chemical composition (EDS, XPS), crystal structure (XRD,EDP), thermal property (in-situ heating & TEM imaging)

IV Group (Ge) Metal Oxide (ZnO)

IV Group (Si)

Growth Experiments:

Selected CVD/PVDprocesses

Metal (Au, In, Sb) nano-particles or colloids asgrowth catalyst

Vapor-liquid-solid growthGrowth on various

substrates (Si, SiO2,quartz, sapphire, …)

Targeted Applications:

TransistorsNonvolatile memoriesSensorsLEDs, lasers

III-V Group (InSb)

Gas Flow Rate

Catalyst Selection

Antimony (Sb) catalyst

Growth Orientations

Ge-NW

Ge-NWIndium (In) catalyst

Elemental Mapping of GeSb Nanowire

Ge Mapping Sb MappingGeSb TEM Image

EDSSAEDTEM

HR-TEM

STM tunneling current to measureGe nanowire band-gap

STM image of Ge nanowire

dI/dV

Energy-efficient, scalable, high-performance transistor

Nanoscale storage media to improve performance/density/energy-efficiency

High-efficiency solar cells & thermoelectrics

Lower detection threshold (2-4 orders) at molecular or atomic level

Component and assembly technology for future electronicsfeaturing transparency, disposability, and flexibility

4

Ge nanowire

NiGe source

NiGe drain

Si-BasedMemories

Nano-EngineeredStorage Devices

DisruptiveStorage Devices

Floating-Gate

Nanocrystal

Fin-Based Memory

MRAM

Phased-Change

Carbon Nanotube

Probe-Based

Polymer

Nanowire

Molecular

RESET SET

RESET

SET

Pore and Lance Cell Structure -Trench Cell Structure Line Cell Structure

Self-Assembly Growth Small size, highly scalable material system Large aspect ratio, etch-free process (one-step CVD) Perfect surface morphology

Nano-Scale Physics Reduced melting point (30~50%) Reduced thermal conductivity (1~2 orders mag.)

Projected Memory Features Ultra-low reset current (< 10A/cell) Extremely low-cost manufacturing Break lithography limit w/ self-assembly

2-D Thin film1-D Nanowire

0-D Nanodot

InSb In2Se3Ge2Sb2Te5

GeTeSbTe

Tm of bulk PCM

Tm of PCM nanowires

• Melting temperature of phase-change nanowire is identified asthe point at which: (1) electrondiffraction pattern disappears, and(2) nanowire starts to evaporate.

• This property is nanowire diameter-dependent: more significantreduction at smaller diameters

24%46%% Reduction

680°C390°CNanowire Tm

890°C725°CBulk Tm

In2Se3GeTe

Thermally induced nanowire encodingwith scanning focused e-beam.

2 3

2/27/2008

Nano-ResearchProgram

NanofabricationModelingSimulation

Novel DeviceTechnology

EmergingNano-Chip

Architecture

Bio/MolecularSelf-Assembly

InorganicNanomaterial

Synthesis

NanostructureCharacterization

Major emphasis will be on nano- and bio-materials self-assembly, physics,modeling, nanofabrication, and emerging device applications in (1)

Nanoelectronics (2) Bioelectronics, and (3) Energy conversion devices

Funding Resources: NSF, DOD, DOE, NASA, SRCClose Industry collaboration

High-PerformanceNanoelectronics

MaterialGrowth & Assembly

Nano-DevicePhysics

Low-DimensionalElectronics

- Carrier transport property- Quantum effects- Strain-induced effects- Thermal property/interface

Thin-Film NanodeviceTechnology

- Transparent devices- Disposable chips

Biological SystemElectronics Interface

- Molecular interface/hybrid devices- Biomimetic devices and circuits

- Field-effect transistors- CMOS/logic units- Quantum-wire devices

- Controlled growth- Large-scale assembly- Composite structures

s-NWs m-NWs CNTs CNFs NPs

Junctions Hetero-structures Interconnects 3-D structures Core-shell

Transistors Switches Storage cells Sensing cells Conversion cells

Large scale array Stacking Multi-substrates Templates

Circuits Functional blocks Sub-systems

Research Phase/Time Scale

Self-assembly: synthesis of structurally complex blocksGuided assembly: use physical or molecular templates

Single Nano-Structures

FunctionalUnits/BlocksAssembly-Driven

FabricationFunctional

DevicesCompositeElements

BasicAssembly

HeterogeneousAssembly

Large-scaleAssembly

Fundamental Issues: How to suppress leakage and power? Innovative selecting device technology?

Passive Crossbar Array Served as interconnect (local & global)

Active Crossbar Array Contains element of programmable

logic, data storage, and sensing

SLBLi-1

BLi BLi+1BLi+2

WLj-1WLj

WLj+1WLj+2

Use of biomolecules asthe building elements in agroup of functionaldevices for informationdetection and processing

Communication betweenbiomolecules to nanoelectronics, e.g., Electron transfer Charge storage Biomolecules-

semiconductor interface Neuron-nanowire

interface

Bio-reaction

ElectronicDetection

Research will be focused on utilizing biomolecules as functional building elements todesign energy-efficient, bio-mimetic devices and circuits with functionality that

currently silicon-based chip technology is conducting.

Research Phase/Time Scale

1st generationSilicon-Based

2nd generationThin-Film-Based

3rd generationNano-Based

4th generationBiology-Based

Why Nanomaterials? High-conversion efficiency (surface-intensive structures) Tunable band-gap (wide spectrum light harvesting) Low-cost (thin film based) Possible materials: s-NWs, m-NWs, CNTs

Why Biomaterials? Bio-enabled solar cells utilizing biomolecules to

convert solar energy into chemical energy (similarto photosynthesis)

Bio-fuel cell use body fluids as a fuel for theelectrical powering of implantable devices